Consumer acceptance of absorbent paper products such as tissue paper products and the like is influenced by the perceived softness of the tissue product. Indeed, the consumer's perception of the desirability of one tissue product over another is based in significant respects on the perceived relative softness of the tissue products; the tissue product that is perceived to be more soft is typically perceived to be more acceptable.
Thus, tissue paper should ideally possess a relatively high emboss definition and bulk, and a relatively high degree of perceived puffiness and softness. The emboss definition and bulk of the tissue paper is commonly found to affect the perceived softness of the tissue paper. In addition, the tissue paper should possess sufficient strength. However, it is typically the case that improving one or more of these parameters of the tissue paper adversely affects one or more of the other parameters. For example, applying a very heavy embossing to the tissue product increases the embossing definition and bulk of the tissue paper, but also increases the friction so that the perceived softness is reduced. Also, a reduction in the strength of the tissue product results. On the other hand, a less heavily embossed tissue product might possess better strength characteristics and smoothness attributes, but the perceived puffiness and softness of the tissue product would be adversely affected.
Conventional deep embossing of two-ply tissue paper involves conveying two plies of tissue paper through a nip formed between a steel roll and a rubber roll. While this type of embossing is able to provide better emboss definition and puffiness, it also increases the back side friction which thus reduces tissue softness. Also, the rather heavy embossing adversely affects the strength of the resulting multi-ply tissue.
U.S. Pat. No. 3,708,366 describes a method of producing two-ply paper towel in which one ply is more severely embossed than the other ply. This patent is not specifically related to the manufacture of tissue paper products. Moreover, the patent describes that the preferred embossments are in the shape of a frustum of a cone. This embossment shape produces non-elongated and rather sharply defined contact regions between the two plies which have been found to result in a paper towel product having a rather harsh feel. While this resulting feel of the product may be acceptable from the standpoint of paper towel products such as that with which the aforementioned patent is concerned, it is a result that is not well suited for tissue paper products.
There thus exists a need for a tissue product having better perceived softness and bulk along with better emboss definition, without unduly degrading the strength characteristics of the tissue product.
A need also exists for a tissue that is heavily embossed, but which does not have the roughened characteristics typically associated with such heavily embossed tissue. When multiple sheets are embossed together, the nubs or protuberances on the back side of the tissue are perceived as being rough by the consumer.
A need also exists for a one ply embossed sheet that does not possess a two-sided look or appearance. One ply embossed sheets are typically embossed with matched steel-to-steel rolls and this produces the undesirable two sided look or appearance. Aside from this, the use of steel-to-steel emboss rolls to produce the one ply embossed tissue creates undesirable paper dust and has a tendency to damage the steel emboss rolls.